PURPOSE: To grind a roll as it is integrated by calculating a profile in accordance with a rolling condition containing its wear amount by a backup roll and the wear amount between upper and lower rolls and requiring a necessary amount of grinding from a difference between this profile and a prescribed profile.

CONSTITUTION: An arithmetic unit 3 predicts the wear profile of a present roll by the rolling data sent from a rolled data collecting device 2. In this case, a predicted value of the wear profile of the present roll is calculated from te rolling condition considering the ware amount by the friction between the roll and the backup roll and the wear amount by the friction between the rolls. A difference between this predicted value and a prescribed target profile is required and amounts of grinding necessary for each section in the barrel direction of the roll are required by calculation. The values for these necessary amounts of grinding are outputted to a grinding controller 1 of grinding to give a desired amount of grinding to each roll.